Where is the hinge point? & what is the moment of inertia of a square?

[randomgamernerd]

Homework Statement

:[/B] A uniform wire of linear mass density λ having three sides each of length 2a is kept on a smooth horizontal surface. An impulse J is applied at one end as shown in the figure. P is the midpoint of AB. Now answer the following questions.
1) The angular velocity of system just after the impulse?

Sorry the image is poorly lit.

Homework Equations

: [/B]Conservation of angular momentum, Iω = Jr
Where R is perpendicular distance of Point of application of J from hinge point.

The Attempt at a Solution

:[/B]
I want to know which point should i consider hinge point. Is it the other end of the rod commected to B and⊥ AB?

 

[kuruman]

I want to know which point should i consider hinge point. Is it the other end of the rod commected to B and⊥ AB?

If you have watched a juggler juggling bowling pins, lit torches or chain saws, about what point would you see these items rotate? Note that the impulse is given very near one end. More specifically, what point (if any) would undergo projectile motion?

 

[randomgamernerd]

If you have watched a juggler juggling bowling pins, lit torches or chain saws, about what point would you see these items rotate? Note that the impulse is given very near one end. More specifically, what point (if any) would undergo projectile motion?

Centre of mass? So i consider the COM as the hinge point?

 

[kuruman]

Yes. After the impulse is delivered, the COM will execute translational motion while simultaneously there will be rotational motion about the COM.

 

[randomgamernerd]

Yes. After the impulse is delivered, the COM will execute translational motion while simultaneously there will be rotational motion about the COM.

O ho, thanks, i will try solving the sum now, and if the answer I get does not match, then I will post my work here again [emoji28]

 

[kuruman]

O ho, thanks, i will try solving the sum now, and if the answer I get does not match, then I will post my work here again [emoji28]

Sounds like a plan.